hello, my name is Sean. im new to the forum, i own a 1993 907ie for 2 years now, i have a EPROM/Chip by Fast by Ferracci installed on the bike, and i also have a FIM UM021, i try both of the chip, with FIM chip installed i have a lot of blow back on the airbox while driving, sometime it die right after the blow back, so i went and get the EPROM chip and installed, it dont do the pop noise when the bike is cool, but when driving for a while and stuck in traffic the bike getting hot and it start doing the pop noise in the air box, i wonder if there a way to fix it??

thanks guys

Sean, any modifications on your bike ? Most chips are for tuned bikes i.e. with slip-on exhaust, sport air filters, modified airbox etc. If your bike is stock it would run too rich with an aftermarket chip.
This wouldn`t explain the backfiring though. When was the last time you had the valve clearances checked and the belts replaced ?

hello and thanks for replying, i have a slip on exhaust with K&N air filter with kinda modified airbox little, well they all come with the bike when i got it, but i havent have a vavle clearances since i got the bike, or belt replace.

do you know when the bike was last serviced ? If the engine backfires through its inlet the main reasons will be incorrect ignition timing or an open inlet valve. Get a service and a compression test.

FbyF should be good w those mods.
But do a valvecheck.